Properties of Electro-Active Paper and Its Potential as a Bio-Inspired Actuator for Special Applications

Abstract

On September 26, 2002, NASA announced that a consortium of six universities including: The University of Maryland, Virginia Tech, The University of Virginia, North Carolina A&T State University, North Carolina State University, and Georgina Tech had submitted the winning proposal for a National Institute of Aerospace. The Institute began formal operations in January of 2003 in Hampton, VA, and its mission included research, education, outreach, and technology transfer. One important focus of the NIA was to stimulate research among its member universities of potential benefit to NASA and to develop additional partnerships to further NIA focus areas. The work described in this paper is such an activity in bio-inspired actuator materials. This work was originally advocated and developed at Inha University, and it is being extended by teams from Inha University, North Carolina A&T State University, and NASA Langley so that the potential for these actuators as devices for special applications is better understood. This paper focuses on important performance characteristics of electro-active paper (EAPap) actuators and the potential of thes actuators to propel autonomous devices. EAPap is a paper that produces large displacement with small force under an electrical excitation. EAPap is made with chemically treated papers with electrodes on both outer surfaces. When electrical voltage is applied to the electrodes, a tip displacement is produced. One drawback in such actuators is that the actual power produced is variable, and the displacement is relatively unstable. Further, the performance tends to degrade in time and as a function of how the papers are processed. Environmental factors also impact the performance of the product including temperature and humidity. The use of such materials in ambulatory devices requires attention to these concerns and further research is needed to find what initial applications are most congruent with EAPap performance and service lift. In this paper, we have extended the knowledge base of EAPap to include additional ranges of temperature and humidity. We have also looked beyond the current tests on cantilevered beam actuators to segmented plate sections and have tested the ability of these actuators to perform as oscillatory devices both in and out of phase, and to chart their performance vs. time humidity and temperature thus emulating a rudimentary wing or walking assembly.

Mechanical properties of cellulose-based electro-active paper

“…Till now very little is known about the mechanical properties of the main constituent of EAPap, the cellulose paper. Recent preliminary tests have been performed to show that this material is anisotropic, with decreased strength in the axial direction, and with moderate temperature and substantial humidity dependency [12]. The objective of this work is to add to the knowledge base of cellulose paper used in EAPap actuators by gathering material properties determined both from static and dynamic loading studies.…”